Venous valve prostheses

ABSTRACT

A venous valve prosthesis includes a frame and a prosthetic valve coupled to the frame. With the venous valve prosthesis implanted in a vein, the prosthetic valve includes a closed configuration wherein an outer surface of the prosthetic valve is in contact with a wall of the vein around a circumference of the prosthetic valve to prevent blood from flowing past the prosthetic valve between the wall of the vein and the outer surface of the prosthetic valve. The prosthetic valve is configured to move to an open configuration such that at least a portion of an outer wall of the prosthetic valve partially collapses away from the wall of the vein in response to antegrade blood flow through the vein to enable blood flow between the outer surface of the prosthetic valve and the wall of the vein.

This application is a continuation application of U.S. patentapplication Ser. No. 14/958,152, filed on Dec. 3, 2015, and entitled,“VENOUS VALVE PROSTHESES,” the entire content of which is incorporatedby reference herein.

FIELD OF THE INVENTION

The following disclosure relates to methods for treating venous valveinsufficiency, and more particularly to venous valves prostheses.

BACKGROUND OF THE INVENTION

Venous valves are found within the vasculature of a mammal, particularlythe veins. Venous valves prevent the backflow of blood duringcirculation. For example, venous valves help to fight backflow of bloodin the legs caused by gravity pulling the blood away from the heart andback towards the feet of a person when standing. However, when venousvalves fail to work properly, blood can flow backwards within the veinsand pool in, for example, the legs. Such pooling of blood can cause theveins to become distended, thereby causing the venous valves to failfurther. This progressively worsening disorder can lead to varicoseveins and chronic venous insufficiency, which is painful and can lead tolower limb ulcerations.

Native venous valves are valves created by thin, overlapping leaflets oftissue that open in response to antegrade pressure, but close inresponse to retrograde pressure. These valves may be reconstructed in asurgical procedure, but are complicated to reconstruct. Known prostheticvenous valves that attempt to replicate the function of the nativeleaflet design are complicated to fabricate, may be damaged duringpercutaneous delivery, and tend to form thrombosis soon afterimplementation. Accordingly, there is a need for venous valve prostheseswhich can be delivered percutaneously. There is also a need for a venousvalve prosthesis which can prevent thrombosis formation and be deliveredto small veins.

BRIEF SUMMARY OF THE INVENTION

The present disclosure provides venous valve prostheses that are easierto fabricate than a thin leaflet design, and are easily deliveredpercutaneously. Further, the disclosed venous valve prostheses mayprevent the formation of thrombus due to the small, continual movementof blood past the prostheses, as well as the prostheses opening andclosing along the wall of a vein rather than in the middle of the vein.The venous valve prostheses may include a prosthetic valve disposed on aframe having a valve section and a stabilizing section.

In general in one aspect, the implementation of the disclosure featuresa venous valve prosthesis including a frame and a prosthetic valvecoupled to the frame. The prosthetic valve includes a closedconfiguration and an open configuration. In the closed configuration,the prosthetic valve is configured such that with the venous valveprosthesis implanted into a vein, an outer surface of the prostheticvalve is in contact with a wall of the vein around a circumference ofthe prosthetic valve to prevent blood from flowing past the prostheticvalve between the wall of the vein and the outer surface of theprosthetic valve. The prosthetic valve is configured to move to the openconfiguration such that at least a portion of an outer wall of theprosthetic valve partially collapses away from the wall of the vein inresponse to antegrade blood flow through the vein to enable blood flowbetween the outer surface of the prosthetic valve and the wall of thevein.

One or more of the following features may be included. The frame mayinclude a plurality of struts and openings defined between the pluralityof struts. In the open configuration, a portion of the prosthetic valvecollapses into the openings between the plurality of struts. Theopenings may be diamond-shaped:

In various embodiments, the frame may include a valve section and astabilizing section. The prosthetic valve is coupled to the valvesection and the stabilizing section is configured to anchor and centerthe venous valve prosthesis within the vein.

The frame may be a self-expanding frame such that the frame exerts aradially outward force on the prosthesis. The radially outward force ispartially overcome by antegrade blood flow to enable the portion of theouter wall of the prosthetic valve to partially collapse inward inresponse to antegrade blood flow through the vein.

The prosthetic valve may include a tapered surface. The prosthetic valvemay further include a substantially cylindrical surface adjacent, alarger end of the tapered surface. In various embodiments, the taperedsurface may include notches, and the prosthetic valve is configured tocollapse in response to antegrade blood flow at the notches. The notchesmay extend into the cylindrical surface.

The prosthetic valve may attain the open configuration that enablesantegrade blood flow between the prosthetic valve and the wall of thevein in response to a pressure gradient caused by antegrade blood flowbeing greater than retrograde blood flow, and the prosthetic valve isconfigured to return to the closed configuration in the absence of thepressure gradient, or when the retrograde blood flow is greater than theantegrade blood flow, to prevent retrograde blood flow between theprosthetic valve and the wall of the vein.

The prosthetic valve may define an opening through a middle portion ofthe prosthetic valve, wherein the opening is open in both the openconfiguration and the closed configuration.

In various embodiments, the prosthetic valve may include slits. In someembodiments, in the open configuration the prosthetic valve maypartially collapse and the slits are opened to enable antegrade bloodflow between the outer surface of the prosthetic valve and wall of thevein upstream of the slits and through the slits. In other variousembodiments, the slits may be located on the tapered section of theprosthetic valve, and in the open configuration the slits open inresponse to the pressure gradient.

In general, in another aspect, the implementation of the disclosurefeatures methods for treating venous valve insufficiency. The method mayinclude delivering a venous valve prosthesis to a site in a vein,wherein the venous valve prosthesis includes a frame and a prostheticvalve. The method further includes deploying the venous valve prosthesisat the site in the vein. The venous valve prosthesis includes a pre-setclosed configuration and an open configuration. In the preset closedconfiguration, the prosthetic valve is in contact with a wall of thevein around a circumference of the prosthetic valve to prevent bloodfrom flowing past the prosthetic valve between the wall of the vein andthe outer surface of the prosthetic valve. The prosthetic valve isconfigured to move to the open configuration such that at least aportion of an outer wall of the prosthetic valve partially collapsesaway from the wall of the vein in response to antegrade blood flowthrough the vein to enable blood flow between the outer surface of theprosthetic valve and the wall of the vein.

One or more of the following features may be included. In variousembodiments, the step of delivering the venous valve prosthesis to thesite in the vein comprises transluminally delivering the venous valveprosthesis to the site. In various embodiment, the venous valveprosthesis may be in a radially compressed delivery configuration duringthe delivering step, and the step of deploying the venous valveprosthesis may include expanding the venous valve prosthesis to aradially expanded deployed configuration. In some embodiments, the frameis self-expanding and the step of expanding the venous valve prosthesisincludes releasing the frame from a sheath such that the frameself-expands to exert a radially outward force on the prosthetic valvesuch that prosthetic valve contacts the wall of the vein. In otherembodiments, the frame is balloon-expandable and the step of expandingthe venous valve prosthesis includes inflating a balloon disposed withinthe frame to expand the frame to exert a radially outward force on theprosthetic valve such that prosthetic valve contacts the wall of thevein.

In embodiments, the prosthetic valve attains the open configuration thatenables antegrade blood flow between the prosthetic valve and the wallof the vein in response to a pressure gradient caused by antegrade bloodflow being greater than retrograde blood flow, and the prosthetic valvereturns to the pre-set closed configuration in the absence of thepressure gradient, or when the retrograde blood flow is greater than theantegrade blood flow, to prevent retrograde blood flow between theprosthetic valve and the wall of the vein.

In various embodiments, the prosthetic valve may define an openingthrough a middle portion of the prosthetic valve, and the opening isopen in both the open configuration and the pre-set closedconfiguration.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing and other features and advantages of the invention will beapparent from the following description of embodiments hereof asillustrated in the accompanying drawings. The accompanying drawings,which are incorporated herein and form a part of the specification,further serve to explain the principles of the invention and to enable aperson skilled in the pertinent art to make and use the invention. Thedrawings are not to scale.

FIG. 1 is a schematic illustration of an embodiment of a venous valveprosthesis.

FIG. 2 is a schematic illustration of an embodiment of a frame of thevenous valve prosthesis of FIG. 1.

FIG. 3 is a schematic illustration of an embodiment of a prostheticvalve of the venous valve prosthesis of FIG. 1.

FIG. 4 is a schematic cross-sectional view of the prosthetic valve ofFIG. 3.

FIG. 5 is a schematic illustration, of the venous valve prosthesis ofFIG. 1 deployed in a vein in a closed configuration.

FIG. 6 is a schematic illustration of the venous valve prosthesis ofFIG. 1 in an open configuration.

FIG. 7 is a schematic cross-section end view of the venous valveprosthesis of FIG. 1 deployed in a vein in an open configuration.

FIG. 8 is a schematic cross-sectional view of the venous valveprosthesis of FIG. 1 deployed in a vein in an open configuration withthe frame removed for clarity.

FIG. 9 is a schematic illustration of a venous valve prosthesisaccording to another embodiment hereof.

FIG. 10 is a schematic illustration of an embodiment of a frame of thevenous valve prosthesis of FIG. 9.

FIG. 11 is a schematic illustration of an embodiment of a prostheticvalve of the venous valve prosthesis of FIG. 9.

FIG. 12 is a schematic cross-sectional view of the prosthetic valve ofFIG. 11.

FIG. 13 is a schematic illustration of the venous valve prosthesis ofFIG. 9 deployed in a vein in a closed configuration.

FIG. 14 is a schematic illustration of the venous valve prosthesis ofFIG. 9 deployed in a vein in an open configuration.

FIG. 15 is a schematic illustration of a venous valve prosthesisaccording to another embodiment hereof.

FIG. 16A is a schematic illustration of the venous valve prosthesis ofFIG. 15 deployed in a vein in a closed configuration.

FIG. 16B is a schematic illustration of the venous valve prosthesis ofFIG. 15 deployed in a vein in an open configuration.

FIG. 17 is a schematic illustration of a delivery device for deliveringa venous valve prosthesis.

FIG. 18 is a schematic illustration of the delivery device of FIG. 17with the sheath retracted.

DETAILED DESCRIPTION OF THE INVENTION

Specific embodiments of the present invention are now described withreference to the figures, wherein like reference numbers indicateidentical or functionally similar elements. The terms “distal” and“proximal” when used in the following description to refer to the venousvalve prosthesis are with respect to blood flow in a vein. Thus, theterms “distal” and “distally” refer to the downstream direction of bloodflow. In a vein, the downstream direction is towards the heart.Similarly, the terms “proximal” and “proximally” refer to the upstreamdirection. The terms “downstream” and “upstream” may be usedinterchangeably with “distal” and “proximal”, respectively. Similarly,the term “antegrade” refers to blood flow in the downstream direction(i.e., towards the heart) and the term “retrograde” refers to blood flowin the upstream direction (i.e., away from the heart). The terms“proximal” and “distal” when referring to a delivery device are withrespect to a position or direction relative to the treating clinician.Thus, “distal” and “distally” refer to positions distant from or in adirection away from the clinician and “proximal” and “proximally” referto positions near or in a direction toward the clinician.

Embodiments herein are directed to a venous valve prosthesis having aframe and prosthetic valve coupled to the frame. The venous valveprosthesis includes a closed configuration and an open configuration.With the venous valve prosthesis implanted in a vein and in the closedconfiguration, an outer surface of the prosthetic valve contacts a wallof the vein around a circumference of the prosthetic valve to preventblood from flowing past the prosthetic valve between the wall of thevein and the outer surface of the prosthetic valve. With the venousvalve prosthesis implanted in a vein and in the open configuration, atleast a portion of the outer surface of the prosthetic valve partiallycollapses away from the wall of the vein in response to antegrade bloodflow through the vein to enable blood flow between the outer surface ofthe prosthetic valve and the wall of the vein. The shear stress of theblood flow over the surface of the prosthetic valve and between theprosthetic valve and the vein wall will help retard the formation ofthrombus by keeping the surface of the prosthetic valve and the veinwall clean, or at least cleaner than prosthetic valves that open fromthe middle of the prosthesis.

Blood flow in the venous system can be caused by movement of muscles,such as from the ankle, calf and thigh muscles, which create antegradeblood flow, or the weight of the blood and the capacitance of the venoussystem, which creates retrograde blood flow. The venous valve prosthesisis configured to open in the presence of antegrade flow, which may causea pressure gradient with a higher pressure on an upstream side of thevenous valve prosthesis and a lower pressure on a downstream side of thevenous valve prosthesis. Conversely, when the retrograde blood flowexceeds the antegrade flow, or the pressure from the antegrade flow andretrograde flow are equal (i.e., no pressure gradient), the venous valveprosthesis is configured to close against the vein wall. Further, aprosthetic valve of the venous valve prosthesis may be configured to befurther urged against the vein wall in the presence of retrograde flow.For example, the thickness and material of the prosthetic valve may beselected so as to enable the prosthetic valve to fill and inflate inresponse to retrograde blood flow, which will further urge the venousvalve prosthesis against the vein wall to prevent retrograde blood flowpast the venous valve prosthesis.

FIG. 18 show a venous valve prosthesis 100 in accordance with anexemplary embodiment hereof. The venous valve prosthesis 100 includes anupstream end 104 and a downstream end 102. The venous valve prosthesis100 includes a frame 110 and a prosthetic valve 150 coupled to the frame110. In the embodiment of FIG. 18 the prosthetic valve 150 is coupled toan outer surface of the frame 110, but it could alternatively be coupledto an inner surface of the frame 110.

The frame 110 is shown without the valve prosthesis 150 in FIG. 2 forclarity. FIG. 2 shows the frame 110 in a radially expanded deployedconfiguration. The frame 110 may also be crimped into a radiallycontracted delivery configuration, as explained in more detail below.The frame 110 is a support structure for maintaining the venous valveprosthesis 100 in a desired location in a vein, as explained in moredetail below. The frame 110 may also be referred to as a stent. As shownin FIGS. 1-2, the frame 110 may have an hourglass shape including avalve section 114, a stabilizing section 112, and a connecting section116 coupling the valve section 114 to the stabilizing section 112.Although the valve section 114, the stabilizing section 112, and theconnecting section 116 are described separately, they may be formed ofunitary structure or may be formed separately and attached to eachother. Further, in an alternative embodiment, the valve section 114 andthe stabilizing section 112 may be joined directly together without theconnecting section 116.

The valve section 114 of the frame 110 includes an upstream end 118, anddownstream end 120, and a central portion 122. As can be seen in FIG. 2,in the radially expanded deployed configuration, the upstream end 118and the downstream end 120 each have a smaller diameter than the centralportion 122. Thus, the central portion 122 of the valve section 114 ofthe frame 110 bulges outwardly relative to the upstream end 118 and thedownstream end 120. Similarly, the stabilizing section 112 includes anupstream end 124, a downstream end 126, and a central portion 128. Aswith the valve section 114, in the radially expanded deployedconfiguration, the upstream end 124 and the downstream end 126 each havea smaller diameter than the central portion 128. Thus, the centralportion 128 of the stabilizing section 112 of the frame 110 bulgesoutwardly relative to the upstream end 124 and the downstream end 128.

The valve section 114 of the frame 110 includes a plurality of struts130 connected by bends 132 and formed into a general tubular shapedefining a lumen 134 therewithin. The struts 130 and the bends 132define openings 136 therebetween. In the embodiment shown in FIGS. 1-8,the openings 136 are generally diamond-shaped. However the openings 136are not required to be diamond shaped. The openings 136 are sized andshaped to enable the prosthetic valve 150 to depress into the openings136, as described in more detail below.

In the embodiment shown, the stabilizing section 112 of the frame 110 isidentical to the valve section 114. Thus the stabilizing section 112includes a plurality of struts 138 connected by bends 140 and formedinto a generally tubular shape, as explained above. The struts 138 andthe bends 140 define openings 142 therebetween. In the embodiment shownin FIGS. 1-8, the openings 142 are generally diamond-shaped. However,the openings 142 are not required to be diamond shaped. Further, inother embodiments, the stabilizing section 112 and the valve section 114are not identical. For example, the configurations of the struts 138 andthe bends 140 of the stabilizing section may be different than thestruts 130 and the bends 132 of the valve section 114. In still otherembodiments, the stabilizing section 112 and the valve section 114 maybe configured similarly but one section may be larger, either indiameter, length or both, than the other (e.g., the stabilizing section112 may be larger than the valve section 114).

The connecting section 116 of the frame 110 includes a plurality ofstruts 144 connecting the downstream end 120 of the valve section 114 tothe upstream end 124 of the stabilizing section 112.

Although the frame 110 has been described in parts, the frame 110 can beconstructed as a single, unitary piece, or the frame 110 may beconstructed as separate pieces and joined together, such as by welding,fusion, adhesives, or mechanical attachment. The struts 130, 138, 144and bends 132, 140 of the frame 110 may be made of materials generallyknown for use in stents. For example, and not by way of limitation, theframe 110 may be made from materials commonly used for stents, such asstainless steel, Nitinol (nickel-titanium shape memory alloy), Elgiloy®(cobalt-chromium-nickel alloy), some biocompatible plastics, as well ascombinations thereof. The frame 110 may be self-expanding or may beballoon expandable.

The frame 110 may include other features not shown. For example, and notby way of limitation, the frame 110 may include barbs or hooks to assistin holding the frame 110 in the desired location in a vein. Inparticular, stabilizing section 112 may include such barbs or hooks.

As shown in FIG. 1, the prosthetic valve 150 is coupled to the valvesection 114 of the frame 110. The prosthetic valve 150 may be coupled tothe frame 110 by any suitable method, such as a friction fit, mechanicalconnection such as sutures, an adhesive connection, or otherconnections. FIGS. 3-4 show the prosthetic valve 150 separated from theframe 110 for clarity. The prosthetic valve 150 includes an upstream end152 and a downstream end 154. The prosthetic valve 150 may be a thinlayer of material defining a conduit 160 therethrough. The upstream end152 includes an upstream opening 156 and the downstream end 154 includesa downstream opening 158 defining upstream and downstream ends of theconduit 160, respectively. As shown in FIGS. 3-4, an upstream portion162 of the prosthetic valve 150 is tapered such that the upstreamopening 156 is smaller than the downstream opening 158. The taperedconfiguration may help provide a smooth transition for the blood flow soas to minimize, or eliminate, the creation of turbulent flow. The sizeof the upstream and downstream openings will depend on the size of thevessel into which the venous valve prosthesis is deployed. In anon-limiting example, the upstream opening 156 may be in the range of0.050-0.080 inches (1.27-2.03 mm) in diameter and the downstream openingmay be in the range of 0.217-0.453 inches (5.5-11.5 mm) in diameter withthe venous valve prosthesis 100 in the radially expanded configuration.In the embodiment shown, the conduit 160 may include a constriction 164adjacent the upstream opening 156. The constriction 164 narrows thediameter of the conduit 160. The diameter of the constriction may dependon the vessel into which the venous valve prosthesis is deployed. In anon-limiting example, the diameter at the constriction 164 may be in therange of 0.016-0.050 inches (0.406-1.27 mm).

The prosthetic valve 150 includes an outer surface 166 and an innersurface 168. The thickness of the prosthetic valve 150 may be in therange of 0.007-0.016 inches (0.178-0.406 mm). The prosthetic valve 150may be made from, for example silicone, ePTFE, or any otherbiocompatible flexible material.

FIG. 5 shows the venous valve prosthesis 100 implanted into a vein 200in the radially expanded configuration and the prosthetic valve 150 in aclosed configuration. The vein 200 may be any vein. However, the venous,valve prosthesis 100 is particularly suited to be implanted into theveins in the leg. For example, and not by way of limitation, the vein200 may be the greater or lesser saphenous veins, the anterior orposterior tibial veins, popliteal veins, and femoral veins. In FIG. 5,the arrow 204 represents the downstream or antegrade direction (towardsthe heart) and the arrow 206 represents the upstream or retrogradedirection (away from the heart).

In the radially expanded configuration, the valve section 114 of theframe 110 pushes the prosthetic valve 150 radially outward and intocontact with an inner surface 203 of a wall 202 of the vein 200.Accordingly, blood flow 208 in the retrograde direction is blockedbetween the outer surface 166 of the prosthetic valve 150 and the innersurface 203 of the wall 202. This closed configuration shown in FIG. 5occurs when the pressure gradient in the vein 200 is zero or approachingzero, for example less than 2 mm Hg, and thus not attempting to pushblood in the antegrade direction, or when the blood flow 208 is movingin the upstream direction 206.

However, even, in the closed configuration, the constriction 164 and theupstream opening 156 of the prosthetic valve 150 enable a small amountof flow in the retrograde direction, as shown by arrow 210 in FIG. 5, oreven in the antegrade direction if there is some blood movement in theupstream direction 206. As explained above, a potential deficiency withexisting venous valve prostheses is the development of thrombosis on thevenous valve prosthesis. It is believed that this small amount of flowduring periods in which the pressure gradient is lower, for example,when a person is sleeping, assists in preventing thrombosis on theprosthetic valve 150. However, larger retrograde flow is prevented bythe blood filling the conduit 160 of the prosthetic valve 150, whichexerts and outward force on the inner surface 168 of the prostheticvalve 150, thus further moving the prosthetic valve to the closedposition.

When pressure is exerted to push blood flow 208 in the downstreamdirection 204, such as by action of the skeletal-muscle pump, the outersurface 166 of the prosthetic valve 150 at least partially collapsesaway from the inner surface 203 of the wall 202. For example, theprosthetic valve may be configured to at least partially collapse whenthe pressure gradient is at least 2 mm Hg. FIGS. 6-8 show schematicallythe prosthetic valve 150 partially collapsing away from the innersurface 203 of the wall 202 such that a gap 212 forms between the outersurface 166 of the prosthetic valve 150 and the inner surface 203 of thewall 202. In the embodiment of FIGS. 1-8, the prosthetic valve 150partially collapses by depressing into the openings 136 formed betweenthe struts 130 and the bends 132 of the valve section 114 of the frame110, as described above. Accordingly, depressions 170 are formed in theprosthetic valve 150 at the openings 136. Thus, the gaps 212 formedbetween the outer surface 166 of the prosthetic valve 150 and the innersurface 203 of the wall 202 enable blood flow 208 in the downstreamdirection 204 between the outer surface 166 of the prosthetic valve 150and the wall 202.

FIG. 7 shows a schematic cross-section end view of the venous valveprosthesis 100 as seen from the section line 7-7 in FIG. 6. As seen inFIG. 7, the upstream end 118 of the valve section 114 of the frame 110is spaced from the wall 202. This is due to the upstream end 118 being asmaller diameter than the central portion 122 of the valve section 114,and thus smaller in diameter than the vein 200. Thus, blood can flowover the upstream end 118 of the valve section 114 and the upstreamportion 162 of the prosthetic valve 150. At the central portion 122 ofthe valve section 114, the struts remain adjacent to the inner surface203 of the wall 202, with the prosthetic valve 150 therebetween.However, in the openings 136, the prosthetic valve 150 collapses fromthe pressure exerted to form depressions 170, thereby forming the gap212 between the outer surface 166 of the prosthetic valve 150 and theinner surface 203 of the wall 202. FIG. 8 shows a cross-sectional viewat the central portion 122 with the frame 110 removed for clarity.

Although the embodiment of FIGS. 1-8 shows that the valve section 114 ofthe frame 110 does not compress in reaction to pressure exerted to pushblood in the downstream direction, the valve section 114 of the frame110, or a portion of the valve section 114, may be constructed toradially compress in reaction to this pressure. Such a compression maycreate a gap around the entire circumference of the prosthetic valve 150between the outer surface 166 of the prosthetic valve 150 and the innersurface 203 of the vein wall 202. In such an embodiment, the stabilizingsection 112 of the frame 110 does not radially compress and thereforeprevents the venous valve prosthesis 100 from migrating within the vein200.

FIGS. 9-14 show a venous valve prosthesis 300 according to anotherexemplary embodiment hereof. The venous valve, prosthesis 300 includesan upstream end 304 and a downstream end 302. The venous valveprosthesis 300 includes a frame 310, a prosthetic valve 350, and anosepiece 380 coupling the prosthetic valve 350 to the frame 310. In theembodiment of FIGS. 9-12 the prosthetic valve 350 is coupled to an outersurface of the frame 310, but it could alternatively be coupled to aninner surface of the frame 310.

The frame 310 is shown without the valve prosthesis 350 in FIG. 10 forclarity. FIG. 10 shows the frame 310 in a radially expanded deployedconfiguration. The frame 310 may also be crimped into a radiallycompressed delivery configuration, as explained in more detail below.The frame 310 is a support structure for maintaining the venous valveprosthesis 300 in a desired location in a vein, as explained in moredetail below. The frame 310 may also be referred to as a stent. As shownin FIGS. 9-10, the frame 310 includes a valve section 314 and astabilizing section 312 coupled to the valve section 314. Although thevalve section 314 and the stabilizing section 312 are describedseparately, they may be formed of unitary structure or may be formedseparately and attached to each other.

The valve section 314 of the frame 310 includes an upstream end 318, adownstream end 320, and a central portion 322. As can be seen in FIG.10, in the radially expanded deployed configuration, the upstream end318 and the downstream end 320 each may have a smaller diameter than thecentral portion 122. Similarly, the stabilizing section 312 includes anupstream end 324, a downstream end 326, and a central portion 328. Aswith the valve section 314, in the radially expanded deployedconfiguration, the upstream end 324 and the downstream end 326 each mayhave a smaller diameter than the central portion 328.

The valve section 314 of the frame 310 includes a plurality of struts330 connected at or adjacent to the upstream end 318 by a hub 332 andformed into a generally tubular shape defining a lumen 334 therewithin.The struts 330 define openings 336 therebetween. In the embodiment shownin FIGS. 9-12, the downstream ends of the struts 330 are not connectedto each other. However, in other embodiments, the downstream ends of thestruts 330 may be connected. The stabilizing section 312 of the frame310 includes a plurality of struts 338 connected at a downstream end bya hub 340. The struts 338 define openings 342 therebetween. In theembodiment shown in, FIGS. 9-12, the upstream end 324 of the stabilizingsection 312 is connected to the downstream end 320 of the valve section314.

Although the frame 310 has been described in parts, the frame 310 may beconstructed as a single, unitary piece or the frame 310 may beconstructed as separate pieces and joined together by any suitablemeans, such as by welding, fusion, adhesives, or mechanical attachment.The struts 330, 338 and hubs 332, 340 of the frame 310 may be made ofmaterials generally known for use in stents. For example, and not by wayof limitation, the frame 310 may be made from materials commonly usedfor stents, such as stainless steel, Nitinol (nickel-titanium shapememory alloy), Elgiloy® (cobalt-chromium-nickel alloy), somebiocompatible plastics, as well as combinations thereof. The frame 310may be self-expanding or may be balloon expandable.

The frame 310 may include other features not shown. For example, and notby way of limitation, the frame 310 may include barbs or hooks to assistin holding the frame 310 in the desired location in a vein. Inparticular, stabilizing section 312 may include such barbs or hooks.

As shown in FIG. 9, the prosthetic valve 350 is coupled to the valvesection 314 of the frame 310. FIGS. 11-12 show the prosthetic valve 350separated from the frame 310 for clarity. The prosthetic valve 350includes an upstream end 352 and a downstream end 354. The prostheticvalve 350 is a thin layer of material defining a conduit 360therethrough. The upstream end 352 includes an upstream opening 356 andthe downstream end 354 includes a downstream opening 358 definingupstream and downstream ends of the conduit 360, respectively. As shownin FIGS. 11-12, the prosthetic valve 350 includes a tapered surface 362.The tapered surface 362 may extend from a cylindrical surface 372towards the upstream end 352 of the prosthetic valve such that adiameter of the conduit 360 at the cylindrical surface 372 is largerthan a diameter of the conduit at the upstream end 352. In anon-limiting example, the upstream opening 356 may be in the range of0.050-0.080 inches (1.27-2.03 mm) in diameter and the diameter D2 of theconduit at the cylindrical surface 372 may be in the range of0.217-0.453 inches (5.5-11.5 mm) in diameter with the venous valveprosthesis 300 in the radially expanded configuration.

The prosthetic valve 350 shown in FIGS. 9-14 includes a pair of notches370 extending longitudinally along the tapered surface 362 and partiallyinto the cylindrical surface 372. The notches 370 are disposeddiametrically opposed to each other. Although two notches 370 are shownin the embodiment of FIGS. 9-12, more or fewer notches 370 may beutilized. For example, and not by way of limitation, three or fournotches 370 may be utilized equally spaced about a circumference of theprosthetic valve 350.

The prosthetic valve 350 includes ah outer surface 366 and an innersurface 368. The thickness of the prosthetic valve 350 may be in therange of 0.007-0.016 inches (0.178-0.406 mm). The prosthetic valve 350may be made from, for example, silicone, ePTFE, or any otherbiocompatible flexible material.

Referring back to FIG. 9, the nose-piece 380 may couple the prostheticvalve 350 to the frame 310. As shown in FIG. 9, the nose-piece 380 mayinclude a bulbous nose 381 which abuts against the upstream end 352 ofthe prosthetic valve 350 and a shaft 384 which is sized to extendthrough opening 356 at the upstream end 352 of the prosthetic valve 350.The shaft 384 extends through an upstream portion of conduit 360 to alocation where the shaft 384 engages the upstream hub 332 of the valvesection 314 of the frame 310. The shaft 384 may engage the hub 332 by afriction fit connection, or may include perturbations which matchopenings in the hub 332. The nose-piece 380 includes a conduit 382extending therethrough which is in communication with the conduit 360 ofthe prosthetic valve 350. The conduit 382 may be in the range of0.016-0.050 inches (0.406-1.27 mm) in diameter.

Although the venous valve prosthesis 300 of FIGS. 9-14 is shown with anosepiece 380, the venous valve prosthesis 300 may not include anose-piece 380. For example, and not by way of limitation, theprosthetic valve 350 may taper to the desired size for the upstreamopening 356. Further, the prosthetic valve 350 may be coupled to theframe 310 by a friction fit, mechanical connection such as sutures, anadhesive connection, or other connections.

FIG. 13 shows the exemplary venous valve prosthesis 300 implanted intothe vein 200 in the radially expanded configuration and in a closedconfiguration. In FIG. 13 the arrow 204 represents the downstreamdirection (towards the heart) and the arrow 206 represents the upstreamdirection (away from the heart).

In the radially expanded configuration, the valve section 314 of theframe 310 pushes the prosthetic valve 350 radially outward and incontact with the inner surface 203 of the wall 202 of the vein 200.Accordingly, blood flow 208 in the downstream direction is blockedbetween the outer surface 366 of the prosthetic valve 350 and the innersurface 203 of the wall 202. This closed configuration shown in FIG. 13occurs when the vein 200 is relaxed and not attempting to push blood inthe downstream direction.

The conduit 382 through the nosepiece 380 in communication with theconduit 360 through prosthetic valve 350 enables a small amount of flowin the upstream direction, as shown by arrow 210 in FIG. 13. Asexplained above, a potential deficiency with existing venous valveprostheses is the development of thrombosis on the venous valveprosthesis. It is believed that this small amount of flow assists inpreventing thrombosis on the prosthetic valve 350.

When pressure is exerted to push blood in the downstream direction 204,the valve section 314 of the frame 310 partially compresses such thatthe outer surface 366 of the prosthetic valve 350 moves away from thewall 202. FIG. 14 shows schematically at least a portion of the valvesection 314 of the frame 310 and the prosthetic valve 350 moving awayfrom the wall 202 such that a gap 212 forms between the outer surface366 of the prosthetic valve 350 and the inner surface 203 of the wall202. In the embodiment of FIGS. 9-14, the frame 310 and the prostheticvalve 350 compress away from the wall 202 particularly at the notches370. However, the notches 370 can be excluded and the entirecircumference of the valve section 314 of the frame 310 may compresssuch that the entire circumference of the prosthetic valve 350 may moveaway the wall 202. Further, even with notches 370, the entirecircumference of the valve section 314 may be configured to compresssuch that the entire circumference of the prosthetic valve 350 movesaway, from the wall 202. Alternatively, the notches 370 may be excludedand the valve section 314 of the frame 310 may be configured such thatonly a portion of the valve section 314 compresses in response toantegrade flow of blood through the vein 200.

In an alternative embodiment, the frame 310 does not compress. Rather,the notches 370 compress into openings 336 between the struts 330 of theframe 310, as described above with reference to the embodiment of FIGS.1-8. In such an embodiment, the notches 370 may extend at leastpartially onto the cylindrical surface 372. Extending the notches 370 atleast partially onto the cylindrical surface 372 may create an area ofweakness that is more easily compressed due to the pressure gradient.

Accordingly, the gaps 212 formed between the outer surface 366 of theprosthetic valve 350 and the inner surface 203 of the wall 202 enableblood flow 208 in the downstream direction 204 between the outer surface366 and the wall 202.

In yet another exemplary embodiment, FIGS. 15 and 16A-16B show a venousvalve prosthesis 400 according to another embodiment hereof. The venousvalve prosthesis 400 includes an upstream end 404 and a downstream end402. The venous valve prosthesis 400 includes a frame 410, a prostheticvalve 450, and a nose-piece 480 coupling the prosthetic valve 450 to theframe 410. In the embodiment of FIG. 15, the prosthetic valve 450 iscoupled to an outer surface of the frame 410, but it could alternativelybe coupled to an inner surface of the frame 410.

FIG. 15 shows the venous valve prosthesis 400 in a radially expandeddeployed configuration. The venous valve prosthesis 400 may also becrimped into a radially compressed delivery configuration, as explainedin more detail below. The frame 410 is a support structure formaintaining the venous valve prosthesis 400 in a desired location in avein, as explained in more detail below. The frame 410 may also bereferred to as a stent. As shown in FIG. 15, the frame 410 includes avalve section 414 and a stabilizing section 412 coupled to the valvesection 414. Although the valve section 414 and the stabilizing section412 are described separately, they may be formed of unitary structure ormay be formed separately and attached to each other.

The valve section 414 of the frame 110 includes a hub 432 at an upstreamend 418 of the valve section 414, and a plurality of struts 430extending in a downstream direction from the hub 432. The hub 432 has areduced diameter as compared to the deployed diameter of the stabilizingsection 412. The struts 430 extend radially outward from the hub 432 inan umbrella-like fashion to a larger diameter at a downstream end 420 ofthe valve section 414. In the embodiment shown, there are six struts430. However, there may be more or fewer struts 430.

The stabilizing section 412 of the frame 410 includes an upstream end424 coupled to the downstream end 420 of the valve section 414. Thestabilizing section 412 further includes a downstream end 426. Thestabilizing section 412 may be a cylindrical stent as in known in theart. In the particular embodiment shown, the stabilizing section 412includes a plurality of rings, each of the rings including a pluralityof struts 438 formed in a zig-zag fashion land coupled to each other bycorresponding bends 440. The rings are coupled to adjacent rings byconnectors 439. The struts 438, bends 440, and connectors 439 formopenings 442 therebetween, as known in the art. The stabilizing section412 may be generally cylindrical tube as known in the art, and can beformed using various stent designs and formation methods.

Although the frame 410 has been described in parts, the frame 410 may beconstructed as a single, unitary piece, or the frame 410 may beconstructed as separate pieces and joined together by any suitablemethod, such as by welding, fusion, adhesives, or mechanical attachment.The struts 430, 438, the hub 432, the bends 440, and the connectors 439of the frame 410 may be made of materials generally known for use instents. For example, and not by way of limitation, the frame 410 may bemade from materials commonly used for stents, such as stainless steel,Nitinol (nickel-titanium shape memory alloy), Elgiloy®(cobalt-chromium-nickel alloy), some biocompatible plastics, as well ascombinations thereof. The frame 410 may be self-expanding or may beballoon expandable.

The frame 410 may include other features not shown. For example, and hotby way of limitation, the frame 410 may include barbs or hooks to assistin holding the frame 410 in the desired location in a vein.

The prosthetic valve 450 is shown in FIGS. 15 and 16A-16B coupled to theframe 410 and generally following the contours of the frame 410. Theprosthetic valve 450 includes an upstream end 452 and a downstream end454. The prosthetic valve 450 is a thin layer of material defining aconduit 460 therethrough. The upstream end 452 includes an upstreamopening 456 and the downstream end 454 includes a downstream opening 458defining upstream and downstream ends of the conduit 460. The prostheticvalve 450 includes a tapered surface 462 which generally follows thecontour of the valve section 414 of the frame 410. The tapered surface462 extends from a cylindrical surface 472 towards the upstream end 456of the prosthetic valve 450 such that a diameter of the conduit 460 atthe cylindrical surface 472 is larger than a diameter of the conduit atthe upstream end 456. In a non-limiting example, the upstream openingmay be in the range of 0.050-0.080 inches (1.27-2.032 mm) in diameterand the diameter of the conduit at the cylindrical surface 472 may be inthe range of 0.217-0.453 inches (5.5-11.5 mm) with the venous valveprosthesis 400 in the radially expanded configuration.

The prosthetic valve 450 includes an outer surface 466 and an innersurface 468. The thickness of the prosthetic valve 450 may be in therange of 0.007-0.016 inches (0.178-0.406 mm). The prosthetic valve 450may be made from, for example, silicone, ePTFE, or any otherbiocompatible flexible material.

The prosthetic valve 450 shown in FIGS. 15 and 16A-16B includes a pairof slits 470 extending through the thickness of the prosthetic valve 450from the outer surface 466 through the inner surface 468. In theembodiment shown in FIG. 15, the slits 470 extend circumferentiallyaround a portion of the circumference of the prosthetic valve 450 andare diametrically opposed with respect to each other. However, there maybe more or fewer slits 470 and they may be arranged differently than theparticular embodiment shown.

The nose-piece 480 may couple the prosthetic valve 450 to the frame 410.As shown in FIG. 15, the nose-piece 480 may include a bulbous nose 481which abuts against the upstream end 452 of the prosthetic valve 450,and a shaft 484 which is sized to extend through the opening 456 at theupstream end 452 of the prosthetic valve 450. The shaft 484 extendsthrough an upstream portion of the conduit 460 to a location where theshaft 484 engages the upstream hub 432 of the valve section 414 of theframe 410. The shaft 484 may engage the hub 432 by a friction fitconnection, or may include perturbations which match openings in the hub432. The nose-piece 480 includes a conduit 482 extending therethroughwhich is in communication with the conduit 460 of the prosthetic valve450. The conduit 482 may be in the range of 0.016-0.050 inches(0.406-1.27 mm) in diameter.

Although the venous valve prosthesis 400 shown in FIGS. 15 and 16A-16Bis shown with a nose-piece 480, the venous valve prosthesis 400 may notinclude a nose-piece 480. For example, and not by way of limitation, theprosthetic valve 450 may taper to the desired size for the upstreamopening 456. Further, the prosthetic valve 450 may be coupled to theframe 410 by a friction fit, mechanical connection such as sutures, anadhesive connection, or other connections.

FIG. 16A shows the venous valve prosthesis 400 implanted into the vein200 in the radially expanded configuration and in a closedconfiguration. In FIG. 16A the arrow 204 represents the downstreamdirection (towards the heart) and the arrow 206 represents the upstreamdirection (away from the heart).

In the radially expanded configuration, the frame 410 pushes theprosthetic valve 450 radially outward and in contact with the innersurface 203 of the wall 202 of the vein 200. Accordingly, blood flow 208in the downstream direction 204 is blocked between the outer surface 466of the prosthetic valve 450 and the inner surface 203 of the wall 202.This closed configuration shown in FIG. 16A occurs when the vein 200 isrelaxed and not attempting to push blood in the downstream direction204.

The conduit 482 through the nose-piece 480 in communication with theconduit 460 through prosthetic valve 450 enables a small amount of flowin the upstream direction 206, as shown by arrow 210 in FIG. 16A. Asexplained above, a potential deficiency with existing venous valveprostheses is the development of thrombosis on the venous valveprosthesis. It is believed that this small amount of flow assists inpreventing thrombosis on the prosthetic valve 450.

When pressure is exerted to push blood in the downstream direction 208,the slits 470 of the prosthetic valve 450 open, enabling blood to flowthrough the slits 470 and into conduit 460, as shown in FIG. 16B. Theslits 470 may open by the valve section 414 of the frame 410 compressingwhile the stabilizing section 412 of the frame 410 remains expanded.Thus, in the example given the stabilizing section 412 of the frameexerts a greater radial force than the valve section 414 of the frame410.

In an alternative embodiment, the slits 470 may be located on thetapered surface 462 of the prosthetic valve 450, and the frame 410 doesnot compress at all. In such an embodiment, the slits may be configuredto open when pressure is exerted to push blood in the downstreamdirection 208, but to close when no pressure is exerted in thedownstream direction 208 and/or when pressure is exerted in the upstreamdirection 206. For example, the slits 470 may be tapered such that theslits only open when pressure is exerted to push blood in the downstreamdirection 208.

While various embodiments of venous valve prostheses have been describedabove, it should be understood that they have, been presented by way ofexample and illustration only, and not limitation. It will be apparentto persons skilled in the relevant art that various changes in form anddetail can be made therein without departing from the spirit and scopeof the invention. Further, each feature of each embodiment discussedherein, and of each reference cited herein, can be used in combinationwith the features of any other embodiment. For example, and not by wayof limitation, the notches of the embodiment of FIGS. 9-14 may be usedin the embodiment of FIGS. 1-8 or the embodiment of FIGS. 15-16.Similarly, the slits of the embodiment of FIGS. 15-16 may be used in theembodiment of FIGS. 1-8 or the embodiment of FIGS. 9-14.

Exemplary materials for the prosthetic valve 150, 350, 450 have beenprovided above. Further, it is desirable for the material for theprosthetic valve 150, 350, 450 to prevent or discourage thrombosisformation thereon when implanted. In an embodiment, the material usedfor the prosthetic valve may have inherentanti-thrombogenic/anti-biofouling properties. Such materials tend tohave properties that prevent the adsorption of proteins and attachmentof platelets. For example, and not by way of limitation, ePTFE may beused for the prosthetic valve.

In another embodiment, the outer surface 166, 366, 466 and/or the innersurface 168, 368, 468 of the prosthetic valve 150, 350, 450 may betreated or coated to make them more resistant to protein/plateletaccumulation. In an embodiment, the treatment may make the material moreinert to biological processes. In another embodiment, the treatment maybe bio-active in nature and directly intervene in a biological processto prevent thrombosis.

Examples of anti-thrombogeneic coatings or treatments includes, but arenot limited to, parylene, Endexo™ available from Interface Biologies,CBAS® Heparin Surface (CARMEDA® BioActive Surface), polyvinylpyrrolidoneand heparin.

In another embodiment, the material for the prosthetic valve 150, 350,450 is selected from materials that rapidly passivate. Such materialsprovide an environment that enables the recruitment and proliferation ofendothelial cells on the surface of the material. Once passivated withendothelial cells, the material is less reactive in terms of proteinabsorption and less prone to thrombosis. A non-limiting, example of suchan approach changes the surface chemistry of the material (for example,surface, charge, surface pH, wettability of the material) with a coatingor surface modification to make it friendlier for cellular recruitmentand proliferation. Non-limiting, examples of such an approach includeusing photoreactive azide treatment to change the hydrophobic of thematerial and plasma treatment to modify the surface chemistry of thematerial.

Other embodiments to make the material of the prosthetic valve 150, 350,450 less susceptible to thrombosis include changing the surfacetopography of the material, or employing porous materials that canaccommodate cell growth and proliferation. Examples of changing thesurface topography include, but are not limited to, sputter coating,adding of hydroscopic hydrogels, etching, spray coating, and vapordeposition.

FIGS. 17-18 show a delivery device 500 for use to deliver a venous valveprosthesis of the present invention. Although FIGS. 17-18 show thedelivery device 500 with the venous valve prosthesis 100 of FIGS. 1-8disposed therein, the delivery device 500 may be used with the venousvalve prosthesis 300 of FIGS. 9-14, the venous valve prosthesis 400 ofFIGS. 15-16, or any other similar embodiments that are within the scopeof the claims.

The delivery device 500 includes a proximal end 502 and a distal end504. A handle 506 is disposed at the proximal end 502. The handle 506may be a luer type device and may include items known to those skilledin the art, such as, but not limited to, seals, actuators, gaskets,strain reliefs, etc. A tip 508 is disposed at the distal end 504 of thedelivery device 500.

The delivery device 500 includes an inner shaft 510, a sheath 512disposed around the inner shaft 510, and a runner 514 disposed betweenthe inner shaft 510 and the sheath 512. In the embodiment shown, theinner shaft 510, the sheath 512, and the runner 514 run substantiallythe length of the delivery device 500 in an over-the-wire manner.However, those skilled in the art would recognize that a rapid exchangetype device may also be utilized.

The inner shaft 510 is a hollow shaft which includes a guidewire lumen511 disposed therethrough. Guidewire lumen 511 is sized and shaped toreceive guidewire 520, as known in the art. The inner shaft 510 iscoupled to the tip 508 at the distal end 504 and attached to the handle506 at the proximal end 502.

The sheath 512 is a hollow, elongate tube which surrounds the innershaft 510. A distal end 516 of the sheath 512 interacts with the tip508. The distal end 516 of the sheath 512 may abut a proximal end of thetip 508 or may overlap a proximal portion of the tip 508, as shown inFIG. 17. The sheath 512 is coupled to the handle 506 such that thesheath 512 may be moved longitudinally relative to the inner shaft 510.The sheath 512 is sized and shaped to confine the venous valveprosthesis 100 in the radially compressed delivery configuration.

The runner 514 is disposed between the inner shaft 510 and the sheath512. A distal portion 518 of the runner 514 includes a plurality ofrunners 522 with slots 524 disposed therebetween, as best seen in FIG.18 and described in more detail below. A proximal portion 526 of therunner 514 is a hollow shaft. The runners 522 are disposed between thevenous valve prosthesis 100 and the sheath 512 with the venous valveprosthesis 100 in the radially compressed delivery configuration and thedelivery device 500 in the delivery configuration, as shown in FIG. 17.The runners 522 protect the venous valve prosthesis 100 during loadinginto the sheath 512.

The delivery device 500 may further include a pusher 516 that abutsagainst an end of the venous valve prosthesis 100 such that the venousvalve prosthesis 100 does not move while the sheath 512 is beingretracted. The pusher 516 is shown in FIG. 17 attached to the innershaft 510, but the pusher 516 may be any similar device to maintain thevenous valve prosthesis 100 in place while retracting sheath 512.Further, the pusher 516 may include an attachment mechanism whichcouples the pusher to a portion of the venous valve prosthesis 100. Theattachment mechanism may be configured to release the venous valveprosthesis after the sheath 512 has been retracted. Spindles withprotrusions about which a portion of the venous valve prosthesis is heldare non-limiting examples of such attachment mechanisms. Such attachmentmechanisms may also be referred to as capture mechanisms.

The delivery device 500 is advanced through the vasculature to alocation such that the venous valve prosthesis 100 disposed therein islocated at a desired site for implantation of the venous valveprosthesis 100. Access to the vasculature is achieved by known methods.The implantation site is a vein, including veins in both the superficialand deep venous systems, such as, but not limited to, greater saphenousveins, lesser saphenous veins, anterior and posterior tibial veins,popliteal veins; and femoral veins. The implantation site is preferablyspaced from a native venous valve.

With the delivery device 500 advanced such that the venous valveprosthesis 100 is at the desired implantation site, the sheath 512 isretracted. The sheath 512 may be retracted using actuators located onhandle 506 or other retraction methods. FIG. 18 shows the deliverydevice 500 with the sheath 512 retracted. As can be seen in FIG. 18, thevenous valve prosthesis 100 is self-expanding such that release from thesheath 512 enables the venous valve prosthesis 100 to radially expand.However, as also seen in FIG. 18, the plurality runners 522 of therunner 514 remain disposed around the venous valve prosthesis 100. Therunners 522 do not resist the radial expansion of the venous valveprosthesis 100 in the manner that the sheath 512 resists expansion.Therefore, the venous valve prosthesis 100 radially expands itself andthe runners 522 when released from the sheath 512. However, theplurality of runners 522 do enable the sheath 512 to be advanced backover the venous valve prosthesis 100 to radially compress the venousvalve prosthesis 100 for various reasons, such as relocation of thevenous valve prosthesis 100 or abortion of the procedure. A transitionarea 528 of the runner 514, shown in FIG. 18, provides a smooth inclinedsurface for the sheath 512 to be advanced back over the venous valveprosthesis 100.

If the physician is satisfied with the placement of the venous valveprosthesis 100, the runner 514 is retracted, leaving the venous valveprosthesis 100 implanted in the vein, as shown in FIG. 5. The runner 514may be retracted using actuators located on handle 506 or otherretraction methods.

With the venous valve prosthesis 100 implanted as shown in FIG. 5, thedelivery device 500 may be removed from the patient.

Alternatively, the venous valve prosthesis 100 may be implanted througha surgical procedure. For example, the vein may be exposed using a cutdown procedure, which may enable a surgeon to better assess the propersize of the venous valve prosthesis 100 to be inserted into the vein, aswell as assess the proper placement of the venous valve prosthesis 100.

Further, as described above with respect to the embodiment shown inFIGS. 1-8, the venous valve prosthesis 100 may include a valve section114 and a stabilizing section 112 that are configured to be differentsizes. For example, one section may be configured to be 10% larger indiameter than the other section. In such an embodiment, both sections112, 114 may include a prosthetic valve 150. The surgeon may then assessthe vein to determine the proper size valve, and remove the prostheticvalve 150 from the section 112 or 114 that is not the proper size, andthat section becomes the stabilizing section 112. It is believed that aproper size for the valve section 114 and prosthetic valve 150 is one inwhich the prosthetic valve 150 makes contact with the inner surface 203of the vein wall 202 without overly distending the vein wall 202.

While various embodiments according to the present invention have beendescribed above, if should be understood that they have been presentedby way of illustration and example only, and not limitation. It will beapparent to persons skilled in the relevant art that various changes inform and detail can be made therein without departing from the spiritand scope of the invention. Further, each feature of each embodimentdiscussed herein, and of each reference cited herein, can be used incombination with the features of any other embodiment. Thus, the breadthand scope of the present invention should not be limited by any of theabove-described exemplary embodiments, but should be defined only inaccordance with the appended claims and their equivalents.

What is claimed is:
 1. A venous valve prosthesis comprising: a framecomprising a valve section and a stabilizing section, wherein thestabilizing section is configured to anchor the venous valve prosthesiswithin a vessel of a patient, the valve section being configured tocompress radially inward from a radially expanded configuration to aradially compressed configuration, wherein the stabilizing section isconfigured to remain expanded when the valve section is in the radiallyexpanded configuration and when the valve section is in the radiallycompressed configuration; and a prosthetic valve coupled to the frame,wherein when the valve section is in the radially expandedconfiguration, the valve section applies a radially outward force on theprosthetic valve, and wherein radial compression of the valve sectionfrom the radially expanded configuration to the radially compressedconfiguration is configured to move the prosthetic valve from a closedvalve configuration to an open valve configuration, wherein when thevenous valve prosthesis is implanted in a vessel and the prostheticvalve is in the open valve configuration, the venous valve prosthesis isconfigured to enable antegrade blood flow between an outer surface ofthe prosthetic valve and a wall of the vessel, and when the prostheticvalve in the closed valve configuration, an outer surface of theprosthetic valve is in contact with the wall of the vessel around aperimeter of the prosthetic valve to prevent blood from flowing past theprosthetic valve between the wall of the vessel and the outer surface ofthe prosthetic valve.
 2. The venous valve prosthesis of claim 1, whereinthe stabilizing section is configured to cause at least a portion of theouter surface of the prosthetic valve to contact the wall in both theopen valve configuration and the closed valve configuration.
 3. Thevenous valve prosthesis of claim 1, wherein the prosthetic valve definesslits, and wherein in the open valve configuration, the slits are openedby the compression of the valve section to enable antegrade blood flowupstream of the slits and through the slits.
 4. The venous valveprosthesis of claim 1, wherein the frame comprises a plurality of strutsand openings defined between the plurality of struts.
 5. The venousvalve prosthesis of claim 1, wherein the prosthetic valve is coupled tothe valve section of the frame.
 6. The venous valve prosthesis of claim1, wherein the frame is a self-expanding frame.
 7. The venous valveprosthesis of claim 6, wherein the stabilizing section of the frame isconfigured to exert a first radially outward force that is greater thana second radially outward force exerted by the valve section of theframe.
 8. The venous valve prosthesis of claim 1, wherein the prostheticvalve includes a tapered surface and a non-tapered surface.
 9. Thevenous valve prosthesis of claim 8, wherein the non-tapered surfaceincludes a substantially cylindrical surface adjacent a larger end ofthe tapered surface.
 10. The venous valve prosthesis of claim 9, whereinthe substantially cylindrical surface defines slits, wherein in the openvalve configuration, the slits are opened by the compression of thevalve section to enable antegrade blood flow upstream of the slits andthrough the slits.
 11. The venous valve prosthesis of claim 1, whereinthe valve section is configured to compress radially inward from theradially expanded configuration to the radially compressed configurationin response to a pressure exerted within the vessel to push blood in adownstream direction, and wherein the stabilizing section is configuredto not radially compress in response to the pressure.
 12. The venousvalve prosthesis of claim 1, wherein the prosthetic valve defines anopening through a middle portion of the prosthetic valve, wherein theopening is open in both the open valve configuration and the closedvalve configuration.
 13. The venous valve prosthesis of claim 1, whereinthe valve section includes a hub at an upstream end of the valve sectionand a plurality of struts extending in a downstream direction from thehub and radially outward from the hub.
 14. The venous valve prosthesisof claim 1, wherein the valve section and the stabilizing section arepart of a single, unitary frame.
 15. The venous valve prosthesis ofclaim 1, wherein the valve section and the stabilizing section areseparate pieces that are joined together.
 16. The venous valveprosthesis of claim 1, wherein the prosthetic valve is disposed about anexterior of the frame.
 17. The venous valve prosthesis of claim 1,wherein the prosthetic valve is disposed within an interior of theframe.
 18. The venous valve prosthesis of claim 1, wherein the frame isa balloon-expandable frame.
 19. A venous valve prosthesis comprising: aframe comprising a valve section and a stabilizing section, wherein thestabilizing section is configured to anchor the venous valve prosthesiswithin a vessel of a patient, and wherein when the venous valveprosthesis is implanted in a vessel, the valve section is configured tocompress radially inward from a radially expanded configuration to aradially compressed configuration in response to a pressure exertedwithin the vessel to push blood through the vessel, the stabilizingsection being configured to not radially compress in response to thepressure; and a prosthetic valve coupled to the frame such that radialcompression of the valve section from the radially expandedconfiguration to the radially compressed configuration moves theprosthetic valve from a closed valve configuration to an open valveconfiguration, wherein when the valve section is in the radiallyexpanded configuration, the valve section applies a radially outwardforce on the prosthetic valve, wherein when the venous valve prosthesisis implanted in the vessel and the prosthetic valve is in the open valveconfiguration, the venous valve prosthesis is configured to enableantegrade blood flow between an outer surface of the prosthetic valveand a wall of the vessel, and when the prosthetic valve in the closedvalve configuration, an outer surface of the prosthetic valve is incontact with the wall of the vessel around a perimeter of the prostheticvalve to prevent blood from flowing past the prosthetic valve betweenthe wall of the vessel and the outer surface of the prosthetic valve.20. The venous valve prosthesis of claim 19, wherein the prostheticvalve defines an opening through a middle portion of the prostheticvalve, wherein the opening is open in both the open valve configurationand the closed valve configuration.
 21. A method comprising: deliveringa venous valve prosthesis to a site in a vessel of a patient, whereinthe venous valve prosthesis includes a frame and a prosthetic valvecoupled to the frame, the frame comprising a valve section and astabilizing section; and deploying the venous valve prosthesis at thesite in the vessel, wherein the stabilizing section is configured toanchor the venous valve prosthesis within the vessel, the valve sectionbeing configured to compress radially inward from a radially expandedconfiguration to a radially compressed configuration, wherein thestabilizing section is configured to remain expanded when the valvesection is in the radially expanded configuration and when the valvesection is in the radially compressed configuration; wherein when thevalve section is in the radially expanded configuration, the valvesection applies a radially outward force on the prosthetic valve, andwherein when the venous valve prosthesis is implanted in a vessel andthe prosthetic valve is in the open valve configuration, the venousvalve prosthesis is configured to enable antegrade blood flow between anouter surface of the prosthetic valve and a wall of the vessel, and whenthe prosthetic valve in the closed valve configuration, an outer surfaceof the prosthetic valve is in contact with the wall of the vessel arounda perimeter of the prosthetic valve to prevent blood from flowing pastthe prosthetic valve between the wall of the vessel and the outersurface of the prosthetic valve.
 22. The method of claim 21, whereindelivering the venous valve prosthesis to the site in the vesselcomprises transluminally delivering the venous valve prosthesis to thesite.
 23. The method of claim 21, wherein delivering the venous valveprosthesis to the site comprises delivering the venous valve prosthesisin a radially compressed delivery configuration to the site, and whereindeploying the venous valve prosthesis comprises expanding the venousvalve prosthesis to a radially expanded deployed configuration.
 24. Themethod of claim 23, wherein the frame is self-expanding and expandingthe venous valve prosthesis comprises releasing the frame from a sheath.25. The method of claim 23, wherein the frame is balloon-expandable andexpanding the venous valve prosthesis comprises inflating a balloondisposed within the frame to expand the frame.